Hey ho, the wind and the rain. Chester's charming open-air theatre has entered its third season with the welcome innovation of a canopy over the seating area, but it's scant compensation for a cast condemned to play much of the second part of Twelfth Night in a downpour. Yet, in a curious sense, the conditions actually enhance the impact of Alex Clifton's production, whose mood, like the sky, darkens threateningly as it goes along. "Now tempests be kind," implores Krupa Pattani's Viola, to ironic laughter from the audience; while Scott Arthur's amiable Sir Andrew Aguecheek takes practical action by sheltering under someone's golfing umbrella. And the unforgiving weather conspires to make the fate of Matthew Rixon's supremely unctuous Malvolio seem crueller than ever – not only must he suffer humiliation and incarceration, he's absolutely drenched as well.

Glyn Maxwell's Masters Are You Mad? is a newly commissioned companion piece that charts the further adventures of the hapless steward. Twelve years have elapsed since the unfortunate incident with the cross-garters, and Orsino's dukedom has become severely depleted as people depart for the mysterious land of Moai, where a cult of love is rumoured to be presided over by a charismatic figure in yellow stockings.

Maxwell evidently means to take the same sort of playful liberties with Twelfth Night that Tom Stoppard inflicted on Hamlet in Rosencrantz and Guildenstern Are Dead. But you never sense that the concept is quite substantial enough to stand apart from its host play, and the blank verse challenges one's inclination to untangle the sense from long, expository, ersatz-Shakespearean speeches. "You mean to jumble language pointlessly and stir the words like soup when nothing much is happening?" says one of the characters, which more or less sums it up.